From a 2012 interview with Jürgen Moltmann:

Were you not then [after the war] obliged to do theodicy?

No. I am convinced that God is with those who suffer violence and injustice and he is on their side. He is not the general director of the theatre, he is in the play.

In your new book, Ethics of Hope, you say that people can be awakened from a dark night of the soul and again experience an unconditional love for life. Is that what happened to you after the war?

Well, three things I still remember. One was the cherry tree blossoming in Belgium in May ‘45, which gave me an overwhelming feeling for life after the darkness and coldness of the prison camp.

And then the humanity of the Scottish workers and their families, who were amazing. They felt solidarity with us because they felt they, too, were victims of violence and injustice from their own government, in 1926 when Churchill [broke] the General Strike [and sent them back] down the mines.

And then there was the Bible I received from a chaplain. These three things convinced me to love life again.